The survey, which polled 1,800 people and covered 12 different providers, asked broadband users to evaluate their providers from zero to five, with five being the highest possible score, across seven categories.

Unreliable connections and speed, frequent price increases and "woeful" customer service were among the major issues contributing to the rankings, Which? added.

BT, which by itself accounts for almost a third of all broadband connections nationwide, scored two across all the seven categories, while TalkTalk earned three stars only in terms of value for money. Sky and the Post Office both scored 48% overall, while EE, Vodafone and Virgin Media did marginally better, recording a 49%, 50% and 52% satisfaction score respectively.

At the other end of the table, Zen Internet recorded an 86% customer satisfaction rating, the highest in the survey, followed by Utility Warehouse with 81%, while John Lewis Broadband, SSE and Plusnet recorded 68%, 66% and 65% respectively.

"The big players still have a long way to go to satisfy their customers, so if you're unhappy with your broadband, complain and look to switch if your service doesn't improve," said Alex Neill, Which? managing director of home services.

A TalkTalk spokesperson said the company was already working on improving its service, in terms of speed and reliability: "Our extensive improvement programme has already led to fewer faults, faster average speeds, shorter times to resolve issues and customers reporting higher satisfaction levels."

Last month, a similar survey published by Ofcom, Britain's telecoms watchdog, found 51% of broadband customers were "very satisfied" with their providers, while 36% were "fairly satisfied".

Out of the four major providers, BT had the lowest rating for "very satisfied customers", scoring 45%, while TalkTalk, Sky and Virgin Media recorded ratings of 49%, 52% and 55% respectively.

However, in response to the survey released by Which?, a BT spokesperson said: "Generally, our broadband performs extremely well for customers and offers very reliable speeds at peak times, according to the latest Ofcom broadband speeds report."

Last month, BT agreed to separate its key broadband services unit Openreach. The country's largest telecoms group and Ofcom said they reached a "long-term regulatory settlement" over Openreach, which runs the national broadband network, after years of criticism within the industry about the poor quality of service provided by the latter.

Rivals, such as Sky or TalkTalk, use Openreach as the ''last mile'' connection between their services and their customers. Many had called for a more complete separation, with BT selling off the unit.